More new paid members joined Prime this year than any other year, Amazon Prime Vice President Greg Greeley said in a statement, adding, "members used digital benefits like Prime Video, Prime Music and Prime Reading more than ever before."

Amazon said last week that it had its "biggest holiday season" this year, and that more than four million people started free trials of Prime or bought memberships in a single week.

Amazon's own Fire TV Stick and Echo Dot topped the list of best-selling products purchased by Prime members in the US.

'Alexa, be more human': Inside Amazon's effort to make its voice assistant smarter, chattier and more like you.